Render tune title, subtitle and composer in Latex/HTML and not in the image. This way the titles remains a constant size even if the image needs to be scaled. And we have that text appearance under our control. I can't find a way of switching off the tune title in abcm2ps, and have worked around by setting the title format to Y0. Y is not a defined ABC header and is not found in any Dottes tune.

X: 1
T: Extension Reel, The
C: Ed Pritchard
M: C
L: 1/4
Q: 180
K: Gmaj
"G" G, D B, D | "C" C E D G | "D" F>G A F | "G" G/B/A/G/ E D |
"G" G, D B, D | "C" C E D G | "D" F>G A F | "G" G2 G2 :|
"G" G>A B G | "Am" c B A D | "Em" G B A G | "C" E2 "D" D2 |
"G" G>A B G | "Am" c B A g | "D" f g a f | "G" g2 g2 :|